The switches in seat controls usually culprit , fuse? yes find it & check first - with test lite on the two metal exposed surfaces or continuity , do pull out/push-in couple of times when done to insure a decent connection .Next ,find seat's electrical connector & try disconnecting / reconnecting several times . N0-Go ? Disconnect connector again and after determining
the "pin-outs" or "which wires do what", use a jumper with inline FUSE - getting it's 12V , like from fuse panel , battery ,wherever . And introduce power into harness AT THE SEAT to see if the seat's motor will operate. Always isolate like this so as not to "BACKFEED" juice upstream which could cause "problems".